Follow-up of oral leukoplakia after carbon dioxide laser surgery

Clinicopathological evaluation of oral leukoplakia: a single-center study of 676 cases in Japan

OBJECTIVES

To analyze the clinical and histopathological characteristics of oral leukoplakia (OL) in the Japanese population and investigate the prevalence and risk factors for epithelial dysplasia (ED) and carcinoma within lesions.

STUDY DESIGN

Data, including age, sex, lesion site, and histopathological features, of 676 cases diagnosed with OL over the previous 10 years were analyzed. Dysplasia and carcinoma prevalence were determined.

RESULTS

In male patients, the most affected site was the gingiva (42.7%), whereas in females, it was the tongue (47.6%). Moreover, ED was more prevalent in males (41.9%), whereas epithelial hyperplasia was more common in females (44.7%). A significant difference was observed between affected sites with regard to the presence of dysplasia. The ED rates by site were 64.6% and 33.7% for the tongue and gingiva, respectively (P < 0.05). The squamous cell carcinoma rates by site were 23.4%, 5.4%, and 3.4% for the tongue, buccal mucosa, and gingiva, respectively (P < 0.05). Logistic regression analysis revealed a higher prevalence of dysplasia in males than it did in females and that the risk for both dysplasia and carcinoma was highest in the tongue.

CONCLUSIONS

Dysplasia is common in OL cases, often showing carcinoma. Early biopsy and interventions are key in OL management.

Designing a Mucoadhesive ChemoPatch to Ablate Oral Dysplasia for Cancer Prevention

Oral cancer has a high mortality rate, and its treatment often causes debilitating complications. More than 90% of oral cancers are oral squamous cell carcinomas (OSCCs) that may develop from clinically recognizable oral premalignant lesions (OPLs). To eradicate OPLs before they turn into cancers, a non-invasive topical formulation is developed based on a novel combination of synergistically acting oxaliplatin (OXP) and mycophenolate (MPS) embedded in a controlled-release mucoadhesive patch fabricated by computer-aided 3D printing. After multiple rounds of testing and optimization, a v6.4 ChemoPatch is designed, which shows sustained release of OXP and MPS in vitro, minimal side leakage of drugs, an average elastic modulus of 2.38 MPa, and suitable drug stability at 4 °C or below for up to 12 months. In vivo analyses show almost all patches adhere to the dorsal tongue surface for 4 hours, and display a sustained release of OXP and MPS to tongue tissue for 3-4 hours. When applied in the 4-nitroquinoline-1-oxide-induced OPL rat model, the OXP-MPS patch significantly ablates dysplastic lesions with no damage to normal epithelial cells and minimal systemic absorption and side effects. This study reports the design of a novel mucoadhesive ChemoPatch as a noninvasive therapy to treat OPLs.

Diagnostic utility of microsurgical carbon dioxide laser excision of oral potentially malignant lesions vs incisional biopsy: a retrospective histopathological review

OBJECTIVE

Complete excision of oral potentially malignant lesions (OPMLs) could result in improved and earlier detection of more severe grades of oral epithelial dysplasia and/or frank malignancy. Transoral microsurgical carbon dioxide laser techniques allow for resection of OPMLs, even those that are extensive. The advantages are improved diagnostic yield, improved viability of the specimen for pathologic evaluation, reduced postoperative morbidity, and easier postoperative clinical surveillance.

STUDY DESIGN

Retrospective review of the histopathology slide material and attendant clinical notes of 31 sequential patients with OPMLs demonstrated the following histopathologic diagnoses on conventional incisional biopsy (CIB): verrucous hyperplasia (2 patients); mild dysplasia (11 patients), moderate dysplasia (3 patients) or severe dysplasia (15 patients); and subsequently, these patients went on to have laser excision biopsy (LEB) of their OPMLs.

RESULTS

Histologic diagnosis was upgraded after LEB in 14 (45%) patients (P < .001), with unexpected findings of cancer in 9 cases (29%) and more severe dysplasia in 5 cases (16%).

CONCLUSIONS

Use of LEB to supplement CIB appears superior in the detection of severe dysplasia and frank malignancy in OPMLs compared with use of CIB alone. Prospective trials are indicated to determine if the superior diagnostic utility of LEB improves patient outcomes with regard to earlier detection of oral squamous cell and/or verrucous carcinoma.

Oral leukoplakia and oral cavity squamous cell carcinoma

Oral leukoplakia is defined as a white oral lesion not related to another disease process. These lesions are largely asymptomatic, and the clinical relevance of oral leukoplakia is primarily tied to its association with oral cavity squamous cell carcinoma. Timely workup and effective management of these lesions can reduce the risk of malignant transformation and promote early diagnosis of invasive tumors. A biopsy should be performed promptly of any persistent or suspicious leukoplakia with subsequent management dictated by histologic findings. Benign lesions can be observed or treated with topical therapy, and dysplastic lesions should be excised. Some risk of malignant transformation remains even after treatment, and close follow-up is required. Oral cavity squamous cell carcinoma is an aggressive malignancy that can result from malignant conversion of oral leukoplakia or occur de novo. These tumors are primarily treated with surgical resection and adjuvant radiation or chemoradiation as dictated by histopathologic findings.

Evaluation of Different Laser-Supported Surgical Protocols for the Treatment of Oral Leukoplakia: A Long-Term Follow-Up

PURPOSE

The aim of this study was to evaluate the long-term success rate of oral leukoplakia treatments by using different laser-supported surgical protocols.

PATIENTS AND METHODS

Overall, 2347 diagnosed homogeneous oral leukoplakias were treated with CO₂ laser and were included in this study. Different surgical protocols (P) were used: P1 (SV = superficial scanning) was a complete superficial vaporization of the leukoplakia by a scanning mode in two passages respecting an overlapping. Only the visible white area was treated in one surgical session independently of the lesion size. P2 (CR1x1) was a complete excision of the lesions until a tissular depth of 1 mm and 1 mm of surrounding healthy-like tissue were attained. The visible white area was treated in one surgical session independently of the lesion size. P3 (CR1x3) was a complete excision of the lesions until a minimum tissue depth of 1 mm and 3 mm of surrounding healthy-like tissue were obtained. The visible white area was treated in one surgical session independently of the lesion size. P4 (PR1x3) was similar to the third one, but for patient comfort, the large lesions of leukoplakias (lesion size higher than 20 mm), the complete surgical excision of the leukoplakia was performed in multiple sessions that were spaced by 1 month (partial surgical removal of 10 mm per session). All patients were recalled at 2 and 8 weeks after surgery, and then every 2 months during the first year, every 4 months during the second year, and once a year for the follow-up period of 6 years. A biopsy was done once a year during the follow-up period in the surgical site when needed. The control consisted of checking the nature and the aspect of the healed mucosa to exclude an eventual recurrence of leukoplakia.

RESULTS

The percentage of permanent success after 6 years of follow-up was 5.7%, 69.7%, 97.8%, and 71.9%, respectively, for the first surgical protocol (SV), the second (CR 1 × 1), the third (CR 1 × 3), and the fourth (PR 1 × 3). The appearance of malignant transformation after laser treatment (during the follow-up period of 6 years) was 20%, 1%, and 0.2%, respectively, for the groups treated by the following protocols: 1 (SV), 2 (CR 1 × 1), and 4 (PR 1 × 3). Only in the third group CR1x3, no dysplasia or malignant transformation was noted. On the contrary, the appearance of malignant transformation in failed treated cases was 21.21% for the protocol 1 (SV), 3% for the protocol 2 (CR 1 × 1), and 0.6% for the protocol 4 (PR 1 × 3).

CONCLUSIONS

The results of this long-term follow-up of treated patients with oral homogeneous leukoplakias pointed out that the surgical laser protocol respecting the complete excision of leukoplakias, in one session, by the removal of a minimum of 1 mm in lesion depth and 3 mm of surrounding healthy-like tissues (CR 1 × 3) offers significantly the highest success rate.

Prevalence of Carcinomatous Foci in Oral Leukoplakia: A Clinicopathologic Study of 546 Indian Samples

INTRODUCTION

Oral Leukoplakia (OL), the most common potentially malignant disorder, is diagnosed clinically on the basis of exclusion of other lesions. In a country like India, where prevalence of oral cancer is very high, the issue of carcinomatous foci within OL at the time of initial diagnosis of leukoplakia has never been addressed before.

AIM

To estimate the prevalence and risk factors for epithelial dysplasia as well as carcinoma within OL lesions at the time of initial clinical presentation in an Indian population with high prevalence of tobacco use.

MATERIALS AND METHODS

Clinical and pathologic data (age, sex, lesion location and histopathologic grading) of 546 cases of leukoplakia were analyzed. The prevalence rate of dysplasia and carcinoma in 546 oral leukoplakia cases was calculated. Univariate analysis was performed to examine risk factors associated with the presence of carcinoma and dysplasia within the lesions.

RESULTS

The male to female ratio in this study was 2:1. Majority of the patients irrespective of sex had a history of tobacco use. Of the total 85% of non-homogeneous lesions and 70% for the homogeneous lesions were illustrating, features of epithelial dysplasia. The prevalence rate of carcinoma was 11.9%. In univariate analysis it was found that lesion site, clinical appearance, tobacco use were strongly correlated with the presence of carcinoma within OL.

CONCLUSION

Our results demonstrate that majority of leukoplakia irrespective of its clinical appearance contain a dysplastic component and significant proportion contains carcinomatous foci. Lesions with certain features are more prone to have carcinomatous foci. However there is always a chance of finding foci of carcinoma in OL anywhere in the oral cavity. Therefore, excision biopsy is always mandatory before long term follow-up and treatment is planned.

[Surgical treatment of patients with oral leukoplakia]

The aim of the study was to elaborate lingual nerve sparing procedure of submandibular gland duct stones extraction. The study involved 43 patients with syalolithiasis treated in Oral Surgery Unit of Central Research Institute of Dentistry and Maxillofacial Surgery in 2013-2015. It was shown that to prevent lingual nerve and artery injury submandibular salivary gland duct should be dissected to the level of obstruction thus allowing adequate visualization of anatomical correlations especially when removing stones from the distal part of the duct.

Comparison of pain and swelling after removal of oral leukoplakia with CO₂ laser and cold knife: a randomized clinical trial

Objective: The aim of this study was to compare conventional surgery with carbon dioxide (CO2) laser in patients with oral leukoplakia, and to evaluate the postoperative pain and swelling. Study design: A total of 48 patients (27 males and 21 females) with a mean age of 53.7 ± 11.7 years and diagnosed with oral leukoplakia were randomly assigned to receive treatment either with conventional surgery using a cold knife or with a CO2 laser technique. A visual analog scale (VAS) was used to score pain and swelling at different postoperative time points. Results: Pain and swelling reported by the patients was greater with the conventional cold knife than with the CO2 laser, statistically significant differences for pain and swelling were observed between the two techniques during the first three days after surgery. Followed by a gradual decrease over one week. In neither group was granuloma formation observed, and none of the patients showed malignant transformation during the period of follow-up. Conclusions: The CO2 laser causes only minimal pain and swelling, thus suggesting that it may be an alternative method to conventional surgery in treating patients with oral leukoplakia.

Key words:Oral leukoplakia, treatment, laser surgery, cold knife, pain, swelling.

Management of potentially malignant disorders: evidence and critique

At a workshop coordinated by the WHO Collaborating Centre of Oral Cancer and Precancer in the United Kingdom, issues related to management of patients affected by oral leukoplakia were discussed by an expert group. The consensus views of the working group are presented here. Although removal of a lesion still seems to be the predominant method of treatment by the majority of relevant health care professionals, no randomized controlled trials have been undertaken to test the hypothesis that excision either by scalpel or laser greatly influences the potential for later malignant transformation within the oral mucosa of an affected individual. Results of observational studies indicate that, although surgery may have a beneficial effect, this is not likely to reduce the risk of later recurrence nor malignant transformation at the same or another site. Medical measures that lessen the size, extent or histopathological features of dysplasia within leukoplakia likewise presently do not seem to be of particular promise, as relapse or later malignant transformation can occur, and there is a risk of adverse effects, particularly with systemic agents (which themselves may be contra-indicated in some individuals). While the risk of malignant transformation, and the development of further potentially malignant disease may theoretically be reduced by cessation of risk activities, such as tobacco usage and alcohol consumption, there remain no good studies that demonstrate that such measures significantly reduce such events.

Three-year follow-up of oral leukoplakia after neodymium:yttrium aluminum garnet (Nd:YAG) laser surgery

Oral leukoplakia is a relatively common lesion with a significant proportion of cases changing into cancer. Since most leukoplakias are asymptomatic, the primary objective of treatment must aim at the prevention of such malignant transformation. The main objectives of the study are to observe (1) the efficacy, safety and acceptability of the neodymium:yttrium aluminum garnet (Nd:YAG) laser in the management of oral leukoplakia; (2) the nature of postoperative complications, if any, associated with laser ablation, and (3) the 3-year prognosis of oral leukoplakia treated with laser. Twenty-eight patients with histologically proven leukoplakia were treated with Nd:YAG laser. From this study, we observed that the patients treated with Nd:YAG laser had only mild to moderate pain, swelling and restricted mouth opening, which peaked between 72 h and 1 week. In a majority of the patients the healing was prolonged, to a maximum of 5 weeks, and there was no clinical evidence of scarring in 26 out of 28 cases. In this study we achieved a cure rate of 92.86% in a 6-month period. Further follow-up after 3 years yielded almost the same result, except that one patient was not available for follow-up. We concluded that Nd:YAG laser is an effective device in the management of oral leukoplakia, which is one of the major pre-cancerous lesions in our country.

Utility of toluidine blue in oral premalignant lesions and squamous cell carcinoma: Continuing research and implications for clinical practice

Toluidine blue (TB) has been shown to aid in the detection and diagnosis of oropharyngeal squamous cell carcinoma (OSCC) and oral premalignant lesions (OPLs). TB has been shown to enhance visualization of oral lesions and assist in identifying sites of increased risk of dysplastic/malignant change and promote biopsy. TB has been shown to identify lesions with molecular changes associated with risk of progression of OPLs to OSCC. A recent prospective longitudinal study showed TB retention in histologic benign lesions and lesions with mild dysplasia that are at increased risk of progression to cancer. Clinical trials show that TB is useful in identifying asymptomatic OSCC and premalignant lesions at risk of progressing to SCC, which might otherwise be undetected until lesions become more advanced. The data supports TB use in oral examination of patients at risk of OSCC.

Factors associated with underdiagnosis from incisional biopsy of oral leukoplakic lesions

OBJECTIVES

Incisional biopsy is accepted by most clinicians as a dependable way of assessing the nature of oral leukoplakia (OL). The aim of the present study was to investigate its reliability and analyze risk factors associated with underdiagnosis from incisional biopsy.

STUDY DESIGN

A cross-sectional retrospective study was conducted in 242 patients with a clinical diagnosis of OL. The discrepancy between provisional diagnosis (from incisional biopsy) and definitive diagnosis (from resection specimen) was analyzed and correlated with clinical variables. Patients who had incisional biopsy taken from a single location and those who received multiple-site biopsies were analyzed separately.

RESULTS

In the 200 cases receiving single-site biopsy, the agreement rate between provisional and definitive diagnoses was only 56%, and underdiagnosis from incisional biopsy was noted in 29.5% of patients. Underdiagnosis rate in the 42 patients receiving multiple-site biopsies was significantly lower (11.9%; P < .05). The rate of unexpected carcinoma in resection specimen was also significantly lower in the multiple-biopsy patients than in the single-biopsy patients (2.4% vs. 12.0%; P < .05). For the single-biopsy group, multivariate analysis revealed that clinical appearance significantly influenced the risk of underdiagnosis and unexpected carcinoma (both P < .05). Compared with homogeneous lesions, nonhomogeneous OL were more prone to be underdiagnosed (adjusted odds ratio [AOR] 2.36, 95% confidence interval [CI] 1.16-4.82) and have carcinoma undetected by incisional specimen (AOR 15.94, 95% CI 2.09-121.72).

CONCLUSIONS

Incisional biopsy was found to have limitations in the assessment of OL, especially for nonhomogeneous lesions. Clinicians should be conscious of the possible underdiagnosis from incisional biopsy, and multiple biopsies should be taken whenever they think that it is necessary.

Carcinoma and dysplasia in oral leukoplakias in Taiwan: prevalence and risk factors

OBJECTIVES

The issue of existence of malignancy within oral leukoplakia has seldom been addressed in Taiwan. The aims of this study were to investigate the prevalence of carcinoma and dysplasia within oral leukoplakia at the time of clinical diagnosis and to identify the associated risk factors in Taiwan.

STUDY DESIGN

The prevalence rate of malignancy and dysplasia in 1046 oral leukoplakias at a university hospital was calculated. Univariate and multivariate analyses by the Mantel-Haenszel method and multiple logistic regression model were performed to examine risk factors associated with the presence of carcinoma and dysplasia within the lesions.

RESULTS

The prevalence rate of carcinoma was 12.9%. The relative risks for the presence of malignancy in leukoplakias on the tongue/floor of mouth and with nonhomogeneous appearance were 2.72- and 28.13-fold by multivariate logistic regression analysis, when compared with those on buccal mucosa and lesions having homogeneous surface (both P < .05). In contrast, patients who both smoked and chewed betel quid had a significantly lower risk for carcinoma than the abstainers (P < .05). A synergistic effect between the 2 major risk factors of clinical appearance and lesion site was evident. Nonhomogeneous leukoplakia on tongue/floor of mouth had a 43.10-fold higher risk compared to homogeneous lesions located on buccal mucosa or other sites (P < .05). However, homogeneous leukoplakia in buccal mucosa or other sites of the oral cavity still had the possibility of having carcinoma within the lesion. The prevalence of dysplasia was 45.6% among the noncancerous leukoplakias with risk factors similar to those for carcinoma.

CONCLUSIONS

Our results demonstrate that some leukoplakias contain a malignant component. Lesions with certain features are more prone to carcinoma, but no clinical attributes can bring certitude. Therefore, all oral leukoplakias should be submitted to microscopic analysis before any definite treatment or long-term follow-up.

Effective management of smoking in an oral dysplasia clinic in London

BACKGROUND

Precancerous lesions precede the development of oral cancer; of several clinical types the most common is leukoplakia. The risk factors include tobacco and excess alcohol use and diets low in antioxidants. Studies concerning the management of risk factors related to oral precancer are meager.

OBJECTIVES

We investigated the effectiveness of smoking cessation at a dysplasia clinic among patients followed up for at least for 12 months.

METHODS

Data from case notes relating to 180 patients with white and red patches of oral mucosa (excluding other benign disorders confirmed by biopsy findings) attending a dysplasia clinic at a teaching hospital in London and seen by one consultant between 1993 and 2003 were transcribed. Effect of referring to a smoker's clinic to receive specialist help was evaluated against brief advice given at the dysplasia clinic +/- medications.

RESULTS

The mean age at the first visit was 48.5 years (+/-12.5), 65% were male, and 88% were white European. One hundred and sixty-two patients (90%) had used tobacco and 83% were current smokers. Of the smokers 95% had smoked over 10 years, the majority smoking over 10 cigarettes per day. Nine were alcohol misusers including two binge drinkers. One hundred and forty-six were diagnosed with oral leukoplakia, 16 with non-homogeneous types (speckled or nodular). Three patients were diagnosed with an erythroplakia. Nineteen per cent exhibited the presence of dysplasia and one subject had in situ carcinoma. Five patients in the sample quit smoking prior to arrival in the dysplasia clinic. Twenty-seven cases (20%) with oral leukoplakia quit smoking while registered as a patient at the dysplasia clinic: 17 of 100 subjects quit with brief advice +/- medications and 10 of 30 following referral to the smoker's clinic. The difference between the two groups was significant for point prevalence abstinence at the last visit to the clinic (minimum 12 months follow up). Out of a total of 180 precancer cases managed in the dysplasia clinic (mean follow up 4.2 years) three patients subsequently developed invasive carcinoma during follow up.

CONCLUSIONS

Smoking cessation needs to be an integral component of management of cases attending a dysplasia clinic and referring to smoker's clinics could help to improve the effectiveness of managing patients with oral precancer to quit smoking.

The use of CO2 laser in the treatment of oral white patches: outcomes and factors affecting recurrence

Laser therapy has been a favoured treatment regime for oral leukoplakia since the mid 1980s. There is no information in the literature regarding factors affecting outcomes in patients with oral leukoplakia. Forty-three patients (mean age 60.3+/-13.6 years) with 73 primary oral leukoplakia were assessed for outcome and factors affecting survival. Dysplastic lesions were found in the majority of patients. The male to female ratio was 1.7:1 with 74% ex- or current smokers, 27% consuming alcohol and 31% continuing to smoke after treatment. The mean observation time was 47.2+/-28.2 months (range 2-102 months). Disease-free survival was 55.4% at 3 years that dropped to 33.9% after 5 years. The malignant transformation rate was 7.3%. No significant prognostic factors were found on univariate analysis but alcohol consumption (P=0.034) and previous malignancy (P=0.018) were found to be significant prognostic indicators using multivariate analysis. Continuation to smoke approached significance (P=0.061). Similar disease-free survival and malignant transformation rates with minimal complications were found as compared to the literature. Recommendations for minimizing recurrence are presented. Long-term follow up and removal of aetiological factors, such as smoking and alcohol, are advised.

Randomized trial of fenretinide (4‐HPR) to prevent recurrences, new localizations and carcinomas in patients operated on for oral leukoplakia: Long‐term results

We assessed the efficacy of fenretinide at preventing relapses, new lesions and carcinomas after surgical excision of oral leukoplakia. In a controlled multicenter study, 170 patients operated on for oral leukoplakias with benign postoperative histology were randomized to 200 mg fenretinide daily for 1 year vs. no intervention. Preliminary analysis indicated that fenretinide had good tolerability and was effective at preventing relapses and new lesions during treatment. Analysis after 5-year follow-up suggested that fenretinide protected against relapses and new lesions up to 19 months after randomization, with both limits of the 95% hazard ratio CI for fenretinide vs. control below 1 for 7 months after randomization. There was also a protective effect against all first events, including cancer, for 25 months, with both limits of the 95% CI below 1 up to 11 months after randomization. Subsequently, risk ratio estimates were unstable. Fenretinide was well tolerated and effective at preventing relapses and new leukoplakias during treatment and after. The trial had to be stopped prematurely for very low recruitment and had insufficient power to reveal any protective effect against oral carcinoma; nevertheless, continuing studies on this promising chemopreventive are justified.

The results of CO2 laser surgery in patients with oral leukoplakia: a 25 year follow up

Oral leukoplakia is an important premalignant lesion of the oral mucosa. We treat this lesion prophylactically with CO2 laser evaporation. In the period from 1976 to 2001, a group of 200 patients with 282 oral leukoplakias were treated by CO2 laser evaporation. In a follow up period of 1-219 months (mean 52), 251 treated leukoplakias (89.0%) did not show a recurrence. Twenty eight (9.9%) local recurrences were observed in 5 to 168 months after treatment. Three (1.1%) squamous cell carcinoma, occurred in the treated area respectively 7, 17 and 19 month after CO2 laser evaporation. This large study with a long follow up shows that laser treatment is a good prophylactic treatment for oral leukoplakia.

Cytologic and DNA-cytometric follow-up of oral leukoplakia after CO2- and Er:YAG-laser assisted ablation: A pilot study

BACKGROUND AND OBJECTIVES

The aim of the present pilot study was to determine therapeutic responses to Er:YAG- and CO(2)-laser ablation in patients with oral leukoplakia as evaluated by means of exfoliative cytology (EC) and DNA-image-cytometry (DNA-I).

STUDY DESIGN/MATERIALS AND METHODS

Ten patients exhibiting a total of 16 lesions affecting a variety of intraoral sites were randomly treated with either (1) an Er:YAG laser (300 mJ/pulse, 10 Hz, defocused mode) (ERL), or (2) an CO(2) laser (4-6 W, 20-50 Hz, focused mode) (CO). Brush (B) and incisional (I) biopsies were obtained from the respective lesions immediately before treatment (B, I) as well as 24-96 weeks postoperatively (B). In cases, in which EC revealed suspicious cells, nuclear DNA-contents were measured using a TV image analysis system.

RESULTS

Both treatment approaches resulted in a complete (C) or partial (P) remission of all investigated lesions. In particular, ERL exhibited C(3), P(5), and CO C(5), P(3). However, in the CO group, two of eight lesions showed a recurrence 32-48 weeks following treatment. Among all investigated lesions, both histological and EC/DNA-I diagnosis revealed no sign of malignancy or dysplasia before or following laser assisted ablation.

CONCLUSIONS

Within the limits of the present study, it may be concluded that both treatment approaches seem to have limitations to achieve predictable eradication of oral leukoplakia.

Lasers in surgical periodontics and oral medicine

Surgical lasers rapidly are becoming part of the periodontal armamentarium. This article discusses the different lasers that are suitable for use on the soft tissues of the periodontium. Various laser-assisted periodontal surgical procedures and laser treatment of diseases of the oral mucosa are discussed.

Management of oral leukoplakia by laser surgery: relation between recurrence and malignant transformation and clinicopathological features

OBJECTIVE

The aim of the present study was to assess the clinical usefulness of laser surgery for oral leukoplakia.

BACKGROUND

Recurrence and/or malignanT transformation of oral leukoplakia have occasionally been observed following laser surgery. It is reported that the rate of recurrence was 7.7-38.1%, while malignant transformation was 2.6-9%.

MATERIALS AND METHODS

A total of 154 oral leukoplakias from 116 patients were treated in our department. Comparisons with the rate of recurrence, malignant transformation and clinical futures, epithelial dysplasia, location, and treatment procedure were examined. To evaluate recurrence and malignant transformation, the cases were restricted to those with a minimum follow-up of 6 months.

RESULTS

A total of 97 lesions fulfilled this criterion. The rate of recurrence had no association with the location or the epithelial dysplasia, although it differed with the treatment procedure. The rate of recurrence in laser surgery was approximately 29%. Malignant transformation was observed in four of 97 lesions. They were observed in 13.6% of tongue cases and 1.8% of gingival cases. Three of four lesions were treated with excision surgery, and the remaining one treated with laser vaporization. Only 1.2% malignant transformation in laser surgery was revealed.

CONCLUSION

Laser excision is suitable for leukoplakia cases on non-keratinized epithelia (i.e., the tongue and buccal mucosa), while laser vaporization is suitable for the gingival cases. Management of oral leukoplakia prevents not only recurrence and malignant transformation, but also postoperative dysfunction. We believe that laser surgery is an excellent procedure.

Laser surgery as a treatment for oral leukoplakia

Various treatment procedures for oral leukoplakia have been reported. However, after some treatments, oral leukoplakia show recurrence and/or malignant transformation, even following complete resection. Furthermore, patients with oral leukoplakia may develop new lesions in other oral cavity locations. Laser surgery for oral mucosal lesions has been reported to have many advantages, and it is widely used in the treatment of oral leukoplakia. In previous studies, recurrence and malignant transformation from the lesion have occasionally been observed following laser surgery. We reviewed the records of oral leukoplakia patients treated with laser surgery to assess its clinical usefulness. It has been reported that the rate of recurrence was 7.7-38.1%, while malignant transformation was 2.6-9% for oral leukoplakia treated with laser surgery. In the present study, there was 29.3% recurrence and 1.2% malignant transformation after laser surgery. This was similar to previous findings. This suggests that non-homogeneous leukoplakia on nonkeratinized epithelia, i.e. the tongue mucosa has a high risk for malignant transformation, so lesions should be excised after detecting abnormal epithelia using vital tissue staining. The wound healing process after laser surgery was satisfactory and no significant complications were observed. Management of oral leukoplakia prevents not only recurrence and malignant transformation, but also postoperative dysfunction: laser surgery is an excellent procedure that is able to overcome these problems.

Mucosal reconstruction using an artificial dermis after KTP laser surgery

OBJECTIVE

The aim of the present study is to assess the clinical effectiveness of the artificial dermis.

BACKGROUND DATA

We have previously observed prolonged postoperative pain and bleeding in patients receiving potassium titanyl phosphate (KTP) laser surgery for oral mucosal diseases.

MATERIALS AND METHODS

The artificial dermis was placed on the wound and fixed to the surrounding oral mucosa by silk suturing. The silicon sheet of the artificial dermis and the sutures were removed on the seventh postoperative day. Postoperative bleeding from the oral mucosa, duration of postoperative pain, and the period required for healing were all assessed clinically. The results were compared to those in a group of similar cases which were treated without the artificial dermis. In this retrospective review, we considered 20 cases of tongue lesion treated by KTP laser (10 leukoplakias, nine squamous cell carcinomas, and one metastatic renal cell carcinoma to the tongue), nine of which were followed by application of an artificial dermis to prevent postoperative pain and bleeding, and 11 of which were not.

RESULTS

No postoperative bleeding was observed in the group of cases treated with an artificial dermis, although it was observed in 45.5% in the group of cases treated without an artificial dermis. There was a statistical difference between these two groups (p < 0.03).

CONCLUSION

It was concluded that use of artificial dermis prevented postoperative bleeding.

Oral leukoplakia: open trial of topical therapy with calcipotriol compared with tretinoin

The aim of the current study was to evaluate, in an open trial, the clinical efficacy of topical calcipotriol compared with tretinoin in the therapy of hyperkeratotic oral lesions (leukoplakia). The study group consisted of 40 patients with histologically proven oral leukoplakias, 20 treated with calcipotriol, the other 20 with tretinoin. The treatment was for 5 weeks and follow-up at 4 months, with clinical assessments at 2, 4 and 5 weeks and regular laboratory assessments. The results showed a significant reduction in lesions (80%), in both calcipotriol and tretinoin groups, with no documented topical or systemic adverse reactions, results maintained at 4 months. Tretinoin however, potentially can induce erythema, angular cheilitis and xerostomia. The study suggests that topical calcipotriol is as effective in the therapy of oral leukoplakia as is topical tretinoin.

Evaluation of surgical excision of non-homogeneous oral leukoplakia in a screening intervention trial, Kerala, India

It is well established that most invasive oral cancers arise from precancerous lesions such as leukoplakia, erythroplakia and oral submucous fibrosis. One of the approaches for control of oral cancer is to detect oral precancerous lesions early in their development and prevent their malignant transformation to invasive cancer either by chemoprevention or by surgical excision of the lesions, with concurrent control of tobacco and alcohol use and other specific aetiological factors. However, the value of specific approaches such surgery in long-term control of lesions and prevention of malignant transformation is not known. We describe our experience with cold knife surgical excision of 59 cases of non-homogeneous leukoplakia of the oral cavity diagnosed in the context of a community-based oral cancer cluster randomised oral cancer screening trial in Kerala, India. Two-thirds of these revealed dysplasia on histology. After a minimum follow-up of 12 months (range 12-37 months) after surgical excision, 44 (74.8%) were remaining disease free with no evidence of recurrent/new lesions; during follow-up, three (5%) developed new luekoplakic lesions, and six (10.1%) developed recurrent lesions, while six (10.1%) could not be traced after treatment. There was no event of malignant change during follow-up. The proportion of subjects remaining with no evidence of disease at 3 years by Kaplan-Meier method of analysis was 62.1% (95% CI: 0.36-0.87). Accrual and long-term follow-up of large number of surgically treated cases may provide valuable leads to management policies of oral leukoplakia, since, as of now, the added value of specific treatments over and above primary prevention by tobacco and alcohol control remains to be established.

Topographical characteristics and shear bond strength of tooth surfaces cut with a laser-powered hydrokinetic system

STATEMENT OF PROBLEM

Erbium lasers, specifically Er;YAG and Er, Cr;YSGG that emit in the near red wavelengths, cut both enamel and dentine. Bonding to these cut surfaces with composites has not been assessed for all laser systems.

PURPOSE

This investigation assessed the shear bond strength of composite bonded to tooth structure treated with an Er,Cr;YSGG-powered hydrokinetic system (HKS, Millennium system) and then was compared with surfaces treated with a carbide bur.

MATERIAL AND METHODS

Extracted human molars were cut into enamel and dentin with both systems. Nonetched and acid-etched subgroups were evaluated. Shear bond strength was measured with an Instron test machine with a knife-edge loading head. In addition, SEMs were evaluated.

RESULTS

There were no significant differences in shear bond strength between etched bur cut (23.3 +/- 2.5 MPa), etched laser-cut enamel (23.7 +/- 4.5 MPa), and nonetched laser-cut enamel (20.5 +/- 2.8 MPa). For nonetched enamel, bond strength values for laser-cut surfaces were significantly higher than the bur-cut surfaces (8.7 +/- 4.3 MPa). Bond strength differences for dentin between bur (14.3 +/- 1.7 MPa) and laser cuts (11.5 +/- 4.3 MPa) were not significant (P =.03). SEM revealed that laser cutting of enamel did not cause formation of a smear layer.

CONCLUSION

There were no significant differences in shear bond strength between etched bur-cut, etched laser-cut, and nonetched laser-cut enamel. With nonetched enamel, bond strength values for nonetched laser-cut surfaces were significantly higher than for the bur-cut surfaces. No bond strength differences between bur and laser cutting existed for dentin. Similar topography was observed for bur and laser prepared surfaces of etched enamel and nonetched dentin.

Promotional effects of CO(2) laser and scalpel incision on 4-NQO-induced premalignant lesions of mouse tongue

BACKGROUND AND OBJECTIVES

CO(2) laser and scalpel incision have been demonstrated to have promotional effects on oral neoplastic lesions. However, a precise understanding has not been achieved as to which modality has a more significant effect on cancer promotion. The purpose of this study was to determine the histological and biological changes after CO(2) laser surgery and scalpel incision in oral premalignant lesions.

STUDY DESIGN/MATERIALS AND METHODS

Premalignant lesions of mouse tongue induced by 4-nitroquinoline-1-oxide (4NQO) in drinking water for 4 months were used in this study. A 2-mm incision was made on the right margin of each mouse tongue, using either a CO(2) laser (group A) or a scalpel (group B). Mice without incisional treatment were used as controls (group C). Seven months after laser and scalpel treatments, hematoxylin-eosin staining and proliferating cell nuclear antigen (PCNA), epidermal growth factor receptor (EGFR), and p53 immunostaining were performed for tongue specimens.

RESULTS

The epithelia of right tongue margins showed more severe dysplasia than those of left tongue margins in both group A and group B. The PCNA labeling indices (LIs) and EGFR expression for right tongue margins were also higher than for left margins in both group A and group B. There was no obvious difference between these two groups. Almost no p53-positive staining was found in either group.

CONCLUSION

CO(2) laser surgery and scalpel incision seem to have similar promotional effects on oral premalignant lesions.

Chemoprevention of head and neck and lung (pre)cancer

Oral cancer is often preceded by precancerous lesions, the most common of which is leukoplakia. Several treatment modalities are available: elimination of the possible cause, cold knife, laser, or cryosurgery, and topical application of bleomycin and 5-fluorouracil. In research, oral leukoplakia is used as a model to study the value of chemoprevention as a strategy to prevent cancer, because its effect is directly visible and material for analysis is easily obtainable from the mouth. In several studies and chemoprevention trials the efficacy of retinoids, retinol and/or beta-carotene on oral leukoplakia has been demonstrated. Second primary tumors occur in 10-30% of head and neck cancer patients and 10% of lung cancer patients. Chemoprevention offers an attractive approach to combat this threat to such patients, which is bound to cast a shadow over their lives. In the last 10-15 years several chemoprevention studies with vitamin A, retinoids or agents working through other mechanisms (antioxidants) have been launched. The largest chemoprevention study in curatively treated early-stage oral cancer, laryngeal cancer and lung cancer (N = 2595) is EUROSCAN, an EORTC study initiated in 1988. End-points are second tumors, local/regional recurrence and distant metastases, and long-term survival rates. Preminary results will be available in 1998.

Topical bleomycin for the treatment of dysplastic oral leukoplakia

BACKGROUND

Because malignant transformation of dysplastic oral leukoplakia has been reported in up to 43% of cases, these lesions must be managed.

METHODS

This study evaluated the use of topical 1% bleomycin in dimethylsulfoxide for the treatment of dysplastic oral lesions. Bleomycin was applied once daily for 14 consecutive days to lesions of the oral mucosa in 19 patients. Immediate posttreatment biopsies and the clinical response were evaluated and clinical follow-up was conducted for as long as possible.

RESULTS

The mean age of the patients at diagnosis was 59.4 years and 74% were tobacco users. Seventy-five percent of patients had resolution of dysplasia at follow-up biopsy, with a mean improvement of two histologic grades of dysplasia after topical chemotherapy. Ninety-four percent of the patients attained at least partial responses. After a mean follow-up period of 3.4 years, 31.6% of patients had no clinically visible lesions and 47.4% of patients had clinically benign lesions of homogeneous leukoplakia or minimal visible leukoplakia. In 2 patients (11%) malignant transformation occurred a mean of 1.75 years after bleomycin treatment.

CONCLUSIONS

Topical bleomycin may prevent the potential progression of leukoplakia through dysplasia to carcinoma. Close follow-up of all patients with dysplasia is required.

Oral leukoplakia: a clinicopathological review

Leukoplakia is the most common premalignant or potentially malignant lesion of the oral mucosa. It seems preferable to use the term leukoplakia as a clinical term only. When a biopsy is taken, the term leukoplakia should be replaced by the diagnosis obtained histologically. The annual percentage of malignant transformation varies in different parts of the world, probably as a result of differences in tobacco and dietary habits. Although epithelial dysplasia is an important predictive factor of malignant transformation, it should be realized that not all dysplastic lesions will become malignant. On the other hand non-dysplastic lesions may become malignant as well. In some parts of the world the tongue and the floor of the mouth can be considered to be high-risk sites with regard to malignant transformation of leukoplakia, while this does not have to be the case in other parts of the world. The cessation of tobacco habits, being the most common known aetiological factor of oral leukoplakia, has been shown to be an effective measure with regard to the incidence of leukoplakia and, thereby, the incidence of oral cancer as well. Screening for oral precancer may be indicated in individuals at risk.

Pulpal response to cavity preparation by an erbium, chromium:YSGG laser-powered hydrokinetic system

The near red-pulsed erbium, chromium:yttrium-scandium-gallium-garnet laser hydrokinetic system, or Er,Cr:YSGG laser HKS, is effective in cutting dental hard tissues. In this longitudinal study, the authors studied the continuously erupting open-apex incisors of New Zealand albino rabbits and the constricted apex teeth of beagles to determine the effects of HKS-produced lesions at various energy levels and of preparations produced by a tapered fissure bur on dental pulp. No pulpal inflammatory responses could be identified either immediately or 30 days after surgery in HKS preparations that removed enamel and dentin without pulp exposure.

The utility of toluidine blue application as a diagnostic aid in patients previously treated for upper oropharyngeal carcinoma

OBJECTIVES

This study evaluated the utility (usefulness) of toluidine blue application as an aid to the recognition and diagnosis of clinically evident lesions in a series of patients previously treated for oral cancer and monitored in a cancer center. In addition to increased risk of recurrence of cancer or new second primary lesions, patients who have had previous treatment for oropharyngeal cancer may be more difficult to assess because of tissue changes that occur as a result of previous radiation therapy.

STUDY DESIGN

Patients with a history of oral malignancy were assessed by clinical examination followed by application of toluidine blue. Biopsy sites were determined on the basis of unaided visual examination and by the findings on toluidine blue application. Biopsy specimens were reviewed by a pathologist blinded to the clinical findings.

RESULTS

Unaided clinical examination identified 78% of carcinoma in situ or invasive malignant lesions compared with toluidine blue application, which identified all (100%) carcinoma in situ or invasive malignant lesions (p = 0.02) and produced no false-negative findings. No differences were found between clinical examination and toluidine application in the detection of dysplastic lesions.

CONCLUSION

Toluidine blue retention was seen in all cases of carcinoma in situ and invasive carcinoma, and no false-negative findings were seen with toluidine blue. When used by a trained and experienced clinician in a cancer center, toluidine blue was a valuable visual aid to clinical examination of oral mucosal lesions.

Effects of an erbium, chromium: yttrium, scandium, gallium, garnet laser on mucocutanous soft tissues

OBJECTIVES

Lasers are effective tools for soft tissue surgery. The erbium, chromium: yttrium, scandium, gallium, garnet laser is a new system that incorporates an air-water spray. This study evaluates the cutting margins of this laser and compares healing with laser and conventional scalpel and punch biopsy-induced wounds.

STUDY DESIGN

New Zealand white rabbits were divided into serial sacrifice groups; the tissues were grossly and microscopically analyzed after laser and convential steel surgical wounding.

RESULTS

Wound margins were found to show minimal edge coagulation artifact and were 20 to 40 mm in width. Laser wounds showed minimal to no hemorrhage and re-epithelialization and collagenization were found to occur by day 7 in both laser and conventional groups.

CONCLUSIONS

The new laser system is an effective soft tissue surgical device; wound healing is comparable to that associated with surgical steel wounds. The minimal edge artifact observed with this laser system should allow for the procurement of diagnostic biopsy specimens.

European School of Oncology Advisory report to the European Commission for the Europe Against Cancer Programme: oral carcinogenesis in Europe

A European School of Oncology Advisory Group has reviewed current knowledge on the epidemiology, treatment and prevention of cancer of the oral cavity. While the major factors in the aetiology of such cancers are thought to be well understood, i.e. tobacco and alcohol consumption, current increases in the occurrence of the disease, especially in young adults throughout Europe, are cause for concern. The reasons for such increases are not clearly evident and the Advisory Group has suggested further work which is required to be carried out to understand the aetiology. In treatment of the disease there have been no major improvements in survival for patients in recent decades and the importance of examining new radiotherapy modalities and defining the role of chemotherapy is emphasized. Primary prevention of oral cancer could be achieved by stopping smoking tobacco, limiting alcohol consumption to a minimum (2-3 drinks per day) and increasing intake of fruits and vegetables. To supplement these actions, while neither population screening programmes nor screening trials could be recommended by the Advisory Group, initial chemoprevention trials have produced some promising results and this represents an interesting area which is the focus of much current research.

Controlled clinical trials with fenretinide in breast cancer, basal cell carcinoma and oral leukoplakia

We are conducting three randomized studies (breast cancer, basal cell carcinoma, oral leukoplakia) and report our methodological approach and accrual here. The aim of the breast cancer study is prevention of a contralateral primary lesion in women already treated for breast cancer; the aim of the basal cell carcinoma study is prevention of recurrences or new occurrence after surgical resection; and the aim of the oral leukoplakia study is prevention of recurrences and new occurrence after CO2 laser resection. The studies were planned according to a randomized design with an intervention arm vs a no-treatment arm. Patients in the intervention group receive 4-HPR at a dose of 200 mg po. The duration of treatment is five years in the breast cancer study, and one year in the basal cell carcinoma and oral leukoplakia studies. The breast cancer study started in March 1987, closing accrual on July 31, 1993. A total of 2,972 patients entered the study; 2,849 were evaluable (1,422 in the 4-HPR group and 1,427 in the control group). Of 2,849 evaluable patients, 867 completed the first five years, 1,142 are still ongoing, and 840 patients have interrupted the study for various reasons. Follow-up is ongoing. The basal cell carcinoma study started in January 1990. As of January 1994, a total of 786 patients had entered the study; 760 were evaluable (363 in the 4-HPR group and 367 in the control group). Of 760 patients in the study, 568 completed the first year, 62 are ongoing and 130 discontinued for various reasons. The study is ongoing.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral precancer: preventive and medical approaches to management

Leukoplakias are among the most common potentially malignant oral lesions. Some are idiopathic, others are related to habits such as tobacco and/or alcohol use. Medical management includes reducing or abandoning these habits, increasing the intake of fruit and vegetables in the diet, and possibly the use of active agents. Retinoids, carotenoids and topical cytotoxic agents show promise, and newer therapies are on the horizon.

Topical bleomycin treatment of oral leukoplakia: a randomized double-blind clinical trial

BACKGROUND

Oral leukoplakia and oral erythroplakia may be associated with benign and dysplastic cellular changes, and are at risk of malignant transformation. Additional means of management of these lesions is needed. The results of nonblinded trials using topical bleomycin in oral leukoplakia indicated the need for phase III study.

METHODS

A prospective, double-blind, randomized trial of topical bleomycin versus placebo was conducted. Bleomycin 1% in dimethylsulphoxide (DMSO) or the carrier was applied for 5 minutes for 14 consecutive days. Clinical assessment and pre-application and post-treatment biopsies were conducted.

RESULTS

Twenty-two patients were randomized. Of the patients who received bleomycin, decrease in clinical size of the lesion was achieved (p = 0.001), and histological reduction in dysplasia was seen (p = 0.094).

CONCLUSIONS

The topical application of bleomycin in DMSO may represent an additional approach to management of oral leukoplakia. The treatment is well-tolerated, and may be considered when the location or extent of the lesion may make surgical excision difficult.

Biology and chemoprevention of head and neck cancer

Head and neck cancer remains a common cause of mortality and morbidity in the United States and throughout the world. In spite of advances in the management of patients with advanced disease, overall survival in this group remains poor. Furthermore, although cancer mortality is lower in patients with early-stage disease, treatment results in significant morbidity, and these patients also face the risk of developing a second primary tumor. Chemoprevention is an innovative approach to decrease overall cancer morbidity and mortality using substances that are capable of preventing cancer progression. Head and neck cancer is an excellent model for chemoprevention, as its biology is consistent with the two concepts important for the development of chemoprevention strategies: field cancerization and multistep carcinogenesis. Several classes of compounds have been evaluated in chemoprevention trials. The most frequently studied agents, the retinoids, were found frequently to induce remissions in patients with oral leukoplakia. Furthermore, retinoids prevented progression to malignancy in one randomized maintenance study. Other agents, including beta-carotene and vitamin E, have been found also to have activity in the management of oral leukoplakia. However, the clinical role of chemopreventive agents in reducing cancer mortality remains to be defined. Two studies, one in head and neck cancer and one in lung cancer, have shown the ability of retinoids to prevent the development of second primary tumors. Current large randomized trials are defining the effectiveness of these agents in reducing the mortality of aerodigestive tract tumors in individuals at high risk.